A friction stir additive manufacturing system and method based on synchronized rotary wire feeding technology

Abstract

The application provides a kind of based on synchronous rotation wire feeding technology's friction stir additive system and method, system includes spindle and wire feeding mechanism, spindle end has stir head, wire feeding mechanism is rotated with stir head synchronously, arc channel is set in the lower part of stir head, arc channel extends from the bottom outer wall of stir head to the region near the middle of lower end face of stir head inwards, the diameter of arc channel gradually reduces from outside to inside;Method steps include: during friction stir additive process, wire feeding mechanism rotates synchronously with spindle, metal wire is heated by induction heating coil, and the metal wire after heating enters lower end face of stir head and is quickly plasticized immediately.The application can not only accurately control the deposition response time of metal wire, but also prevent the clogging problem in friction stir additive process, and the problem of interrupted deposition process due to the clogging of shaft shoulder cavity, and the requirement for the matching relationship between the rotation speed of stir head and the wire feeding speed is lower.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to a friction stir additive manufacturing system and method based on synchronous rotary wire feeding technology. Background Technology

[0002] Friction stirring additive manufacturing technology is a solid-phase additive manufacturing technology that consumes materials such as powder, rods, and filaments, and uses the heat generated by the rotational friction between the tool head and the substrate to process the powder, rods, or filaments to be added into a plasticized state and deposit them onto the substrate.

[0003] In existing technologies, document CN114799480A discloses a method and apparatus for continuous filament feeding and solid-state friction stir additive manufacturing. This method involves feeding filamentous additive material through a feed port into the apparatus, where it interacts mechanically with a screw. Under the rotation of the screw, the filament is shredded, compressed, and plasticized before being extruded from the outlet and deposited onto the substrate surface. Document CN115647569B discloses a robotic continuous filament feeding friction stir additive manufacturing apparatus and a curved surface additive manufacturing method. This method uses a continuous filament feeding friction stir additive manufacturing module, driven by a flexible serial robot, to conform to the complex curved surface of the additive component, moving at a certain speed and gradually lifting along the deposition direction, ultimately forming a complete solid-state additive manufacturing layer. However, the aforementioned solutions have several problems, including the high likelihood of material blockage in the shoulder cavity, interrupting the deposition process. This is one of the current challenges in friction stir additive manufacturing technology, and the high requirements for the matching relationship between the tool head rotation speed and the filament feeding speed. More importantly, none of the existing friction stir additive manufacturing equipment and methods can precisely control the deposition response time of the metal wire (the time from the moment the metal wire is cut to its deposition on the workpiece). Even with the two continuous additive manufacturing schemes mentioned above, the deposition response time of the metal wire can only be controlled within 2 to 3 seconds. Summary of the Invention

[0004] This invention provides a friction stir additive manufacturing system and method based on synchronous rotary wire feeding technology. This solution can control the deposition response time of metal wire to within 0.5 seconds, while effectively preventing material blockage during the friction stir additive manufacturing process.

[0005] The present invention adopts the following technical solution.

[0006] A friction stir additive manufacturing system based on synchronous rotary wire feeding technology includes a main shaft and a wire feeding mechanism. The main shaft is connected to the main body of the friction stir equipment, and a stirring head is connected to the end of the main shaft. The wire feeding mechanism is arranged on the side of the stirring head and rotates synchronously with the stirring head during the friction stir additive manufacturing process. An arc-shaped channel is provided at the bottom of the stirring head, extending from the outer wall of the bottom of the stirring head inward to the area near the middle of the lower end face of the stirring head, and the diameter of the arc-shaped channel gradually decreases from the outside to the inside. During the friction stir additive manufacturing process, the metal wire continuously fed by the wire feeding mechanism enters the inner end of the arc-shaped channel laterally and is continuously plasticized under the spinning action of the lower end face of the stirring head.

[0007] To better prevent material blockage, the arc-shaped channel adopts an arc-shaped open groove set at the bottom of the mixing head.

[0008] As a preferred embodiment, the arc-shaped channel has two arc-shaped channels, which are symmetrically arranged, and each arc-shaped channel is matched with a wire feeding mechanism.

[0009] Furthermore, the wire feeding mechanism includes a cantilever fixedly connected to the upper part of the main shaft, on which a wire spool is mounted. The axis of the wire spool is perpendicular to the main shaft. A support is mounted inside the wire spool and above the stirring head. A roller assembly is mounted on the support, and an induction heating coil is mounted inside the roller assembly. The axis of the induction heating coil coincides with the center line of the arc-shaped channel entrance. The metal wire drawn from the wire spool passes through the roller assembly, then through the induction heating coil, and then enters the arc-shaped channel laterally. As a preferred embodiment, multiple cantilever arms are symmetrically arranged on the upper part of the main shaft.

[0010] As a preferred embodiment, both the cantilever and the bracket are in the shape of a gate, and the cantilever and the bracket are oriented in the same direction.

[0011] To further improve the quality of additive manufacturing, a guide groove or protrusion is provided on the lower end face of the mixing head and next to the arc-shaped channel.

[0012] A method of using the aforementioned friction stir additive manufacturing system, comprising the following steps: Step 1: Install the wire spool with the metal wire on the cantilever, then pull out the metal wire and pass it sequentially through the roller assembly and the inner cavity of the induction heating coil; Step 2: Turn on the main unit of the friction stir equipment and set the process parameters for friction stir additive manufacturing, including setting the wire feeding rate of the wire feeding mechanism and the induction heating temperature. Step 3: Move the stirring head to the additive starting point on the workpiece, and then perform friction stirring additive manufacturing according to the set path. During the friction stirring additive manufacturing process, the wire feeding mechanism rotates synchronously with the spindle and heats the metal wire through the induction heating coil. The heated metal wire then enters the lower end face of the stirring head and is rapidly plasticized. Furthermore, it also includes step 4: after completing the additive manufacturing according to the single-layer additive manufacturing path, control the stirring head to gradually lift away from the surface of the deposited layer, continue to feed the wire for a period of time, then retract and switch to the next single-layer additive manufacturing path to continue additive manufacturing. This ensures that the filler at the last position (end) is sufficient and without defects, and also allows the feeding force of the continuous metal wire to clean the residual plasticized metal material in the arc-shaped channel.

[0013] As a preferred solution, the wire feeding rate of the wire feeding mechanism is adjusted by controlling the drive motor of the roller assembly.

[0014] In order to achieve a more accurate deposition response time for the metal wire, the distance between the inner end of the induction heating coil and the entrance of the arc-shaped channel should not exceed 20mm.

[0015] As a preferred embodiment, the inner diameter of the induction heating coil is no more than twice the diameter of the metal wire to ensure that the heating depth can be rapidly transmitted to the center of the metal wire. The induction heating power can be adaptively adjusted according to the additive material. The solution of this invention can realize the additive manufacturing of both low-melting-point metals and high-melting-point metals (while current traditional wire feeding additive manufacturing is mainly for low-melting-point metals such as aluminum alloys, and high-melting-point metals such as steel are difficult to achieve the ideal plasticization state smoothly).

[0016] Beneficial effects: This invention not only precisely controls the deposition response time of metal wire to within 0.5 seconds, but also effectively prevents material blockage during the friction stir additive manufacturing process. It avoids the problem of material blockage in the shaft shoulder cavity interrupting the deposition process, and has lower requirements for the matching relationship between the stirring head rotation speed and the wire feeding speed. It also offers the advantage of convenient and flexible adjustment of the wire feeding rate. Using this invention, during additive manufacturing process switching, metal residue can be quickly cleaned without disassembling the tool head (stirring head), completing the cleaning of metal residue within five seconds (while traditional tool head cleaning takes several minutes or even tens of minutes). This invention can also broaden the range of process parameters required for friction stir additive manufacturing. It achieves a continuous feeding friction stir additive manufacturing process, avoiding joints left in the deposition layer during material exchange intervals and improving the overall performance of additive components. During friction stir additive manufacturing, two wire discs can be fed with metal wires of different materials, and the proportion of different components can be controlled by differential feeding to achieve additive manufacturing of graded functional materials. This invention can match metal wires of different sizes with the stirring head, can be flexibly applied to different scenarios, and can achieve additive manufacturing of large-size, complex-structure components through multi-layer, multi-pass deposition paths. Attached Figure Description

[0017] Figure 1 This is a partial schematic diagram of the friction stir additive manufacturing system in Example 1. Figure 2 This is a schematic diagram of the stirring head of the friction stir additive system in Example 1. Figure 3 This is a schematic diagram of the stirring head of the friction stir additive system in Example 2. Figure 4 This is a schematic diagram of the stirring head of the friction stir additive system in Example 3. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0019] Combination Figures 1 to 2 As shown, a friction stir additive manufacturing system based on synchronous rotary wire feeding technology includes a main shaft 1 and a wire feeding mechanism. The main shaft 1 is connected to the main body of the friction stir equipment, and a stirring head 7 is connected to the end of the main shaft 1. The wire feeding mechanism is arranged on the side of the stirring head 7 and rotates synchronously with the stirring head 7 during the friction stir additive manufacturing process. An arc-shaped channel 9 is provided at the lower part of the stirring head 7. The arc-shaped channel 9 extends from the outer wall of the bottom of the stirring head 7 inward to the area near the middle of the lower end face of the stirring head 7, and the diameter of the arc-shaped channel 9 gradually decreases from the outside to the inside. During the friction stir additive manufacturing process, the metal wire continuously fed by the wire feeding mechanism enters the inner end of the arc-shaped channel 9 laterally and is continuously plasticized under the spinning action of the lower end face of the stirring head 7.

[0020] In this embodiment, the arc-shaped channel 9 adopts an arc-shaped open groove set at the bottom of the stirring head 7. There are two arc-shaped channels 9, which are arranged symmetrically, and each arc-shaped channel 9 is matched with a wire feeding mechanism.

[0021] In this embodiment, the wire feeding mechanism includes a cantilever 2 fixedly connected to the upper part of the main shaft 1. A wire spool 3 is provided on the cantilever 2. The axis of the wire spool 3 is perpendicular to the main shaft 1. A support 10 is provided inside the wire spool 3 and above the stirring head 7. A roller assembly 4 is provided on the support 10. An induction heating coil 6 is provided inside the roller assembly 4. The axis of the induction heating coil 6 coincides with the center line of the entrance of the arc-shaped channel 9. The distance between the inner end of the induction heating coil 6 and the entrance of the arc-shaped channel 9 is 10mm. The diameter of the entrance of the arc-shaped channel 9 is 8mm. The inner diameter of the induction heating coil 6 is 1.5 times the diameter of the metal wire. The metal wire drawn from the wire spool 3 passes through the roller assembly 4 and then through the induction heating coil 6, and then enters the arc-shaped channel 9 laterally. Both the cantilever 2 and the support 10 are gate-shaped structures, and the cantilever 2 and the support 10 face the same direction. The wire spool 3 is rotatably mounted on the side plate of the cantilever 2, and the roller group 4 is mounted on the side plate of the support 10. The side plate of the support 10 is also provided with through holes or notches for the metal wire to pass through. The diameter of the through holes or notches is larger than the diameter of the metal wire. The drive wheel shaft of the roller group 4 is connected to the drive motor. The wire feeding rate of the wire feeding mechanism is adjusted by controlling the drive motor of the roller group 4.

[0022] A method of using the friction stir additive manufacturing system of this embodiment includes the following steps: Step 1: Install the wire spool 3 with metal wire on the cantilever 2, then pull out the metal wire and pass it sequentially through the roller group 4 and the inner cavity of the induction heating coil 6; Step 2: Turn on the main unit of the friction stir equipment and set the process parameters for friction stir additive manufacturing, including setting the wire feeding rate of the wire feeding mechanism and the induction heating temperature. Step 3: Move the stirring head 7 to the additive starting point on the workpiece, and then perform friction stirring additive manufacturing according to the set path. During the friction stirring additive manufacturing process, the wire feeding mechanism rotates synchronously with the spindle 1 and heats the metal wire through the induction heating coil 6. The heated metal wire then enters the lower end face of the stirring head 7 and is quickly plasticized. Furthermore, it also includes step 4: after completing the additive manufacturing according to the single-layer additive manufacturing path, control the stirring head 7 to gradually lift away from the surface of the deposited layer, continue to feed the wire for a period of time (such as 3-5 seconds), then retract it and directly switch to the next single-layer additive manufacturing path to continue additive manufacturing. This ensures that the filler at the last position (end) is sufficient and without defects, and also allows the feeding force of the continuous metal wire to clean the residual plasticized metal material in the arc-shaped channel 9.

[0023] In traditional solutions (such as document CN115647569B), matching the stirring head rotation speed and wire feeding speed requires comprehensive consideration of forming quality and shoulder cavity structure. While meeting forming quality requirements, the wire feeding speed matching range is narrow and the matching difficulty is high. In contrast, the solution in this embodiment, due to the cooperation between the aforementioned specific structure of the stirring head and the wire feeding mechanism, broadens the range of process parameters required for friction stir additive manufacturing, especially the wire feeding speed matching range. This significantly reduces the requirements for the matching relationship between the stirring head rotation speed and the wire feeding speed. The main consideration when matching the stirring head rotation speed and the wire feeding speed is forming quality. While meeting forming quality requirements, the wire feeding speed matching range is wider and the matching difficulty is lower, offering the advantage of convenient and flexible adjustment of the wire feeding rate. Example 2

[0024] Combination Figure 3 As shown, a friction stir additive manufacturing system based on synchronous rotary wire feeding technology, referring to Embodiment 1, differs from Embodiment 1 mainly in that: a protrusion 11 or a guide groove is provided on the lower end face of the stirring head 7 and next to the arc-shaped channel 9, which is beneficial to further improve the additive manufacturing quality. Example 3

[0025] Combination Figure 4 As shown, a friction stir additive manufacturing system based on synchronous rotary wire feeding technology, referring to Embodiment 1, differs from Embodiment 1 mainly in that: the arc-shaped channel 9 adopts an arc-shaped variable diameter channel 12 located at the lower part of the stirring head 7, and the distance between the lower edge of the inlet of the arc-shaped variable diameter channel 12 and the lower end face of the stirring head 7 is 2mm.

[0026] During friction stir additive manufacturing, the metal wire is driven by the roller assembly 4 to pass smoothly through the induction heating coil 6 and is rapidly heated. The heated metal wire then enters the arc-shaped channel 9 laterally. When the tip of the metal wire contacts the lower end face of the stirring head 7, it is rapidly plasticized. As the stirring head 7 spins forward, the plasticized metal material is additively deposited onto the workpiece. The heated metal wire is rapidly fed to the lower end face of the stirring head 7 and plasticized without needing to be cut. Theoretically, the faster the wire feeding speed, the faster the deposition response time of the metal wire, which can be precisely controlled within 0.5 seconds.

[0027] Because of the aforementioned specific structure of the arc-shaped channel 9 and the wire feeding method, the plasticized metal material will not accumulate or pass through the cavity of the shoulder, and there will be no problem of material blockage in the shoulder cavity that interrupts the deposition process, thus fundamentally solving the material blockage problem in the friction stir additive manufacturing process.

[0028] When an additive manufacturing process ends and it is time to switch to the next process, only a small amount of metal residue remains in the arc-shaped channel 9 at the moment of shutdown. The embodiment can be used to clean (poke) the metal residue in the arc-shaped channel 9 with the help of a needle-like tool, or by continuing to feed metal wire into the arc-shaped channel 9 to clean the metal residue. The entire cleaning process can be completed within five seconds (while cleaning the residue in the traditional tool head takes several minutes or even tens of minutes and requires disassembling the tool head for operation), making the operation very convenient.

[0029] This invention realizes a continuous feeding friction stir additive manufacturing process, avoiding joints left in the deposition layer during material exchange intervals and improving the overall performance of additive components. During the friction stir additive manufacturing process, two wire discs can be fed with metal wires of different materials, and the proportion of different components can be controlled by differential feeding to realize the additive preparation of graded functional materials. Multiple cantilever arms can also be added to increase the number of components and improve the preparation capability of graded functional materials. This invention can match metal wires of different sizes with stirring heads, can be flexibly applied to different scenarios, and can realize the additive manufacturing of large-size, complex-structured components through multi-layer and multi-pass deposition paths.

Claims

1. A friction stir additive manufacturing system based on synchronous rotary wire feeding technology, comprising a main shaft (1) and a wire feeding mechanism, the main shaft (1) being connected to the main body of the friction stir equipment, and a stirring head (7) being connected to the end of the main shaft (1), characterized in that: The wire feeding mechanism is arranged on the side of the stirring head (7). The wire feeding mechanism rotates synchronously with the stirring head (7) during the friction stirring additive manufacturing process. An arc-shaped channel (9) is provided at the bottom of the stirring head (7). The arc-shaped channel (9) extends from the bottom outer wall of the stirring head (7) to the area near the middle of the lower end face of the stirring head (7). The diameter of the arc-shaped channel (9) gradually decreases from the outside to the inside. During the friction stirring additive manufacturing process, the metal wire continuously fed by the wire feeding mechanism enters the inner end of the arc-shaped channel (9) laterally and is continuously plasticized under the spinning action of the lower end face of the stirring head (7). The arc-shaped channel (9) adopts an arc-shaped open groove set at the bottom of the stirring head (7). The inner end of the arc-shaped channel (9) is flush with the lower end face of the stirring head (7).

2. The friction stir additive manufacturing system according to claim 1, characterized in that: The arc-shaped channel (9) has two, and the two arc-shaped channels (9) are arranged symmetrically, with each arc-shaped channel (9) matched with a wire feeding mechanism.

3. The friction stir additive manufacturing system according to any one of claims 1-2, characterized in that: The wire feeding mechanism includes a cantilever (2) fixedly connected to the upper part of the main shaft (1), a wire spool (3) is provided on the cantilever (2), the axis of the wire spool (3) is perpendicular to the main shaft (1), a bracket (10) is provided inside the wire spool (3) and above the stirring head (7), a roller group (4) is provided on the bracket (10), an induction heating coil (6) is provided inside the roller group (4), and the axis of the induction heating coil (6) coincides with the center line of the entrance of the arc-shaped channel (9); the metal wire drawn from the wire spool (3) passes through the roller group (4) and then passes through the induction heating coil (6), and then enters the arc-shaped channel (9) laterally.

4. The friction stir additive manufacturing system according to claim 3, characterized in that: The cantilever (2) and the bracket (10) are both in the form of a gate, and the cantilever (2) and the bracket (10) are oriented in the same direction.

5. The friction stir additive manufacturing system according to claim 4, characterized in that: A guide groove or protrusion is provided on the lower end face of the stirring head (7) and next to the arc-shaped channel (9).

6. A method of using the friction stir additive manufacturing system according to any one of claims 1-5, characterized in that the steps include... include: Step 1: Install the wire spool (3) with metal wire on the cantilever (2), then pull out the metal wire and pass it through the roller group (4) and the inner cavity of the induction heating coil (6) in sequence; Step 2: Turn on the main unit of the friction stir equipment and set the process parameters for friction stir additive manufacturing, including setting the wire feeding rate of the wire feeding mechanism and the induction heating temperature. Step 3: Move the stirring head (7) to the additive starting point on the workpiece, and then perform friction stirring additive manufacturing according to the set path. During the friction stirring additive manufacturing process, the wire feeding mechanism rotates synchronously with the main shaft (1) and heats the metal wire through the induction heating coil (6). The heated metal wire then enters the lower end face of the stirring head (7) and is rapidly plasticized.

7. The method of use according to claim 6, characterized in that: The wire feeding rate of the wire feeding mechanism is adjusted by controlling the drive motor of the roller group (4).

8. The method of use according to claim 6, characterized in that: The distance between the inner end of the induction heating coil (6) and the entrance of the arc-shaped channel (9) is no more than 20 mm; the inner diameter of the induction heating coil (6) is no more than twice the diameter of the metal wire.

9. The method of use according to claim 6, characterized in that, It also includes step 4: after completing the additive manufacturing according to the single-layer additive manufacturing path, control the stirring head to gradually lift it away from the surface of the deposited layer, continue to feed the wire for a period of time, then retract it and directly switch to the next single-layer additive manufacturing path.

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